Iterative method for optical modelling of perovskite-based tandem solar cells.

We present an iterative method to model the optical properties of a complete semitransparent perovskite solar cell. It is based on spectroscopic characterizations and accounts for porosity and incoherence effects. We provide the complex refractive indices of each layer, and we identify the main sources of optical losses. The optical model is also coupled to an electrical model of 4T perovskite/silicon tandem solar cells. It allows to evaluate the interplay between the optical and electrical losses, and the balance between the efficiency of the top and bottom cells. These models provide an effective way to design future tandem devices.

Psoas proximal insertion as a simple and reliable landmark for numbering lumbar vertebrae on MRI of the lumbar spine.

OBJECTIVE: To evaluate the value of psoas muscle proximal insertion for correct numbering of the lumbar vertebrae in MRI, in particular in case of lumbosacral transitional vertebra (LSTV). METHODS: Two radiologists assessed 477 MRI scans of the lumbar spine with a sagittal localizer sequence on the whole spine for numbering vertebrae caudally from C2. Proximal insertion of the psoas was determined as the most proximal vertebra with psoas over half of its body on coronal T2 STIR sequence. The last lumbar vertebra was named considering both its number and the presence or absence of LSTV according to Castellvi classification. These same parameters were also assessed on 207 PET-CT scans of another cohort including the whole spine. RESULTS: Proximal insertion of the psoas was L1 in 94.1% of cases: 98.5% in case of modal anatomy, 81.4% in case of LSTV, and 51.7% in case of missing or supernumerary lumbar vertebra without LSTV. There was no statistically significant difference between MRI and CT data. The inter-reader agreement for determination of psoas proximal insertion was excellent (kappa = 0.96). CONCLUSION: Proximal insertion of the psoas muscle is a helpful marker for correct numbering of the lumbar vertebrae in MRI and to detect a complete lumbosacral segmentation anomaly. KEY POINTS: • Proximal insertion of the psoas muscle can be easily identified on a coronal T2 STIR sequence. • Psoas proximal insertion on the spine almost always designates the first lumbar vertebra and is helpful to accurately number all lumbar vertebrae, especially in case of lumbosacral transitional vertebra. • Conversely, when psoas muscle does not insert five lumbar bodies above the apparent lumbosacral joint, the probability of variation in the number of lumbar vertebrae is high.

Correction to: In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study.

The original article [1] contains errors in Table 1 affecting some of the presented oligonucleotide sequences and readthrough values in Table 1.

Contribution of brain CT in the diagnosis of tuberculous meningitis: a case report from Djibouti.

Tuberculous meningitis, a serious disease with high mortality and morbidity, remains frequent in countries with endemic tuberculosis. Its non-specific presentation often delays the introduction of appropriate treatment. Its definitive diagnosis requires isolation of Mycobacterium tuberculosis from cerebrospinal fluid, although this test may be negative without conclusively ruling out this diagnosis. A presumptive diagnosis should be reached as soon as possible through a body of clinical evidence, including the lumbar puncture findings. Brain computed tomography (CT) with and without contrast medium injection is helpful for the diagnosis of tuberculous meningitis and its complications. We discuss the features of CT and their value in relation to a case of tuberculous meningitis in Djibouti, as well as the role of CT in managing this disease.

Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots.

We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X(+), X(-)) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting δ1=0.14 meV (δ1=0.47 meV); g-factor g = 2.12 (g = 1.71); diamagnetic shift γ=2.5 µeV T(-2) (γ =1.3 µeV T(-2)). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.

Biometry of the normal stapes using stapes axial plane, high-resolution computed tomography.

OBJECTIVE: The stapes is difficult to analyse on computed tomography because of the small size of its components and its oblique orientation. The stapes axial plane, parallel to the superstructure, seems optimal for this purpose. The present study assessed the position of the stapes axial plane with respect to the usual axial plane including the lateral semicircular canal, and sought to measure the main dimensions of the stapes. METHODS: This retrospective study comprised 208 computed tomography scans of normal ears. Stapes length and width, footplate thickness and incudostapedial joint width were measured. RESULTS: The stapes axial plane was directed upward, outward (44°) and forward (12°) with respect to the lateral semicircular canal plane. Mean head-to-footplate distance was 3.7 mm and mean superstructure width was 2.7 mm. Mean footplate thickness was 0.27 mm on stapes axial plane versus 0.48 mm on lateral semicircular canal plane. Incudostapedial joint width was systematically less than 0.7 mm. CONCLUSION: Stapes dimensions on stapes axial plane were close to anatomical data, particularly for footplate thickness.

Ultrasonographic evaluation of gastric content during labour under epidural analgesia: a prospective cohort study.

BACKGROUND: Women in labour are considered at risk of gastric content aspiration partly because the stomach remains full before delivery. Ultrasonographic measurement of antral cross-sectional area (CSA) is a validated method of gastric content assessment. Our aim was to determine gastric content volume and its changes in parturients during labour under epidural analgesia using bedside ultrasonography. METHODS: The cut-off value corresponding to an increased gastric content was determined by ultrasound measurement of antral CSA in six pregnant women in late pregnancy before and after ingestion of 250 ml of non-clear liquid. Antral CSA was then measured twice in 60 parturients who presented in spontaneous labour: when the anaesthesiologist was called for epidural analgesia catheter placement, and at full cervical dilatation. Patient-controlled epidural analgesia was performed with a solution of ropivacaine and sufentanil. RESULTS: After liquid ingestion, antral CSA (mm(2)) increased from 90 (range, 80-151) to 409 (range, 317-463). A CSA of 320 was taken as cut-off value. The feasibility rate of antral CSA determination was 96%. CSA decreased from 319 [Q1 158-Q3 469] to 203 [Q1 123-Q3 261] during labour (P=2×10(-7)). CSA was >320 in 50% of parturients at the beginning of labour vs 13% at full cervical dilatation (P=0.006). CONCLUSIONS: Bedside ultrasonographic antral CSA measurement is feasible in pregnant women during labour and easy to perform. The observed decrease in antral CSA during labour suggests that gastric motility is preserved under epidural anaesthesia. The procedure could be used to assess individual risk of gastric content aspiration during labour.

Designing quantum dots for solotronics.

Solotronics, optoelectronics based on solitary dopants, is an emerging field of research and technology reaching the ultimate limit of miniaturization. It aims at exploiting quantum properties of individual ions or defects embedded in a semiconductor matrix. It has already been shown that optical control of a magnetic ion spin is feasible using the carriers confined in a quantum dot. However, a serious obstacle was the quenching of the exciton luminescence by magnetic impurities. Here we show, by photoluminescence studies on thus-far-unexplored individual CdTe dots with a single cobalt ion and CdSe dots with a single manganese ion, that even if energetically allowed, nonradiative exciton recombination through single-magnetic-ion intra-ionic transitions is negligible in such zero-dimensional structures. This opens solotronics for a wide range of as yet unconsidered systems. On the basis of results of our single-spin relaxation experiments and on the material trends, we identify optimal magnetic-ion quantum dot systems for implementation of a single-ion-based spin memory.

Clinical-radiological correlation after functional endoscopic sinus surgery in patients with chronic rhinosinusitis: interest of a sinonasal aerial volumetry.

BACKGROUND: Although a CT scan is often performed after functional endoscopic sinonasal surgery (FESS) in patients with chronic rhinosinusitis, its role hasn`t been firmly established. The goal of this study is to investigate the correlation between symptoms and CT findings before and after FESS for chronic rhinosinusitis. In addition, the interobserver agreement for both sinonasal aerial volumetry and CT score is assessed. METHODS: Thirty-three patients surgically treated for chronic rhinosinusitis were included in this prospective study. Conventional and modified Lund-Mackay scores and sinonasal volumetry were determined by two radiologists before (M0), at 3 months (M3) and 1 year (M12) after surgery. The symptoms were evaluated by the 22-item SinoNasal Outcome Test (SNOT-22). RESULTS: Change of SNOT-22 and air volume were significantly correlated between M0 and M12, but not between M0 and M3, for both readers. Compared to other scores, volume had the best intraclass correlation coefficient and reproducibility, according to the Bland-Altman analysis. No correlation was found between SNOT-22 and CT scores before and after surgery, except between M12 and M0 for one reader. CONCLUSION: The correlation between CT scan and symptoms is low or absent. The measurement of sinonasal air volume is best correlated with the symptoms after surgery, with the best inter-observer agreement.

Electrodeposition of ZnO nanorod arrays on ZnO substrate with tunable orientation and optical properties.

The electrodeposition of ZnO nanorods on ZnO:Al films with different orientations is reported. The influence of the total charge exchanged during electrodeposition on the nanorod's geometry (length, diameter, aspect ratio and surface density) and the optical transmission properties of the nanorod arrays is studied on a [0001]-oriented ZnO:Al substrate. The nanorods are highly vertically oriented along the c axis, following the lattice matching with the substrate. The growth on a [1010] and [1120] ZnO:Al-oriented substrate with c axis parallel to the substrate leads to a systematic deviation angle of 55 degrees from the perpendicular direction. This finding has been explained by the occurrence of a minority orientation with the [1011] planes parallel to the surface, with a preferential growth on corresponding [0001] termination. Substrate crystalline orientation is thereby found to be a major parameter in finely tuning the orientation of the nanorod array. This new approach allows us to optimize the light scattering properties of the films.

[Retrospective study conducted in northern Finistère about the role of breast MRI in normal breast screening, experience in 51 patients]. / Etude rétrospective dans le Nord-Finistère sur la place de l'IRM mammaire devant un bilan sénologique normal, à propos de 51 cas.

OBJECTIVES: To study the role and indications of breast MRI in normal breast screening. PATIENTS AND METHODS: Retrospective study of 51 patients (mean age of 51 years) conducted in northern Finistère. Each patient had a normal (BI-RADS 1 or 2) breast screening (mammography and echography). Four indications for MRI were chosen: screening of high-risk patients, high-density breasts, radio-clinical discordance, and breasts prostheses. Breast MRI were reviewed according to BI-RADS classification. Abnormalities categorized in BI-RADS 4 or 5 were confirmed histologically. RESULTS: Thirteen patients underwent histological analysis. Nine invasive carcinomas were identified (six invasive lobular carcinomas (ILC), two mixed carcinomas, one invasive ductal carcinoma). For these patients, the reason for performing MRI was a radio-clinical discordance. DISCUSSION AND CONCLUSION: The study demonstrates the breast MRI value for radio-clinical discordance and the key role of MRI in diagnostic challenge of ILC. In literature review, MRI has a role even if breast screening is normal: radio-clinical discordance, screening of patients with high-risk, breasts prostheses in certain cases. Breast density comes as an additional criteria to perform this exam.